x86, mm: Break down init_all_memory_mapping

Will replace that with top-down page table initialization.
New API need to take range: init_range_memory_mapping()

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-21-git-send-email-yinghai@kernel.org


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>